black plug

[bklyn400ex]

here's my prob, i have a pipe, kn filter and holes in the airbox, i never rejetted, and it runs ok, but when i pull out the plug it comes out black every time, its carbon not oil what should i do do i go smaller than stock jets?


thanx chris

[oynot400]

Get a new plug and check it again. If you were running rich before and running on the lean side now it would be hard to tell. ;)

[northeast400]

Do you bog it down alot? what kind of gas do you use?

[Steve-o 400EX]

Cheap gas can give a little carbon, but not a whole lot. Do you have an outerware on the k&N? If u dont it could be letting dirt into the motor. You definately want to go up in jet sizes with the mods u have. Get a new plug, rejet, get an outerware for the k&N and run at least 92 octane gas and see if it still does it. Try a 42 pilot and a 152 main jet.

[bklyn400ex]

i run only 93 octane, i change the plug everytime i ride, i only ride like 2 days out of the month and every time i take out the plug its black and not a wet black, its carbon, i dont have an outerwear, but i have plugs with filters in the holes in the airbox so no dirt gets in. Should i still try to go up a little higher on the jets

thanx

[bklyn400ex]

it only bogs the first couple minutes after i get it started, then it rides fine, but its hard to keep it idleing

[bklyn400ex]

i pulled apart the carb today and someone put in a 155 main jet, i ordered a 150, but the shop sent me a 145 he told me it was the next step up from stock. do u think it will be better with the 145 than the 155 i mean it was blackkkkkk with the 155 so im thinking the 145 is a good start, then go up from there what do u think